Refactor TrackerCategory constructor.
Refactor TrackerCategory constructor.

svn path=/trunk/; revision=604

GNOME/rygel,jku/rygel,Tarnyko/rygel,GNOME/rygel,Pelagicore/Media-Manager-Rygel-patched,GNOME/rygel,luisbg/rygel,jku/rygel,Pelagicore/Media-Manager-Rygel-patched,Tarnyko/rygel,Pelagicore/Media-Manager-Rygel-patched